Transparent gas barrier films composed of a polymer film base having an deposited layer of an inorganic substance (or inorganic oxide) such as aluminum oxide, silicon oxide, and magnesium oxide formed on a surface thereof by a physical vapor deposition (PVD) technique such as vacuum deposition, sputtering, and ion plating, or a chemical vapor deposition (CVD) technique such as plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition have been used as materials for packaging of foodstuffs and pharmaceuticals and for electronic devices such as Flat-screen TV and solar battery that are required to be impermeable to various gases including water vapor and oxygen.
Gas barrier properties improvement techniques that are available now include, for instance, forming a layer composed mainly of silicon oxide and a compound containing at least one of the group consisting of carbon, hydrogen, silicon, and oxygen on a base by the plasma CVD technique using a gas mixture containing vapor of an organic silicon compound and oxygen to achieve improved gas barrier properties while maintaining transparency (Patent document 1). 0Gas barrier properties improvement techniques that do not use a film formation process include stacking organic layers of an epoxy compound and silicon based oxide layers deposited by plasma CVD alternately on a base to produce a multi-layered gas barrier film that is free from cracks or defects caused by stress in the film.